VARICELLATUA.] LECAHO-LECIDKKI. 511 



63. VARICELLARIA Xyl. Mem. 

 Soc. Cherb. t. v. (1857) p. 117 ; Lich. 

 Scand. p. 182. Thallus thinly crusta- 

 ceous, pulveraceous or subleprarioid. 

 Apothecia variolarioid or sorediiform 

 (in convex verrucas), pale, carneo- 

 punctate or suffused ; thecae ventri- 

 cose, monospored ; spores very large, 

 1 -septate, colourless ; paraphyses 

 scanty, subdiscrete, slender, variously 

 arcuate. Sperm ogones not yet seen. 



Among other characters well distin- 

 guished from Pertusaria by the septate 

 spores, which are also the largest observed 

 among lichens. Only a single species is 

 known, which has recently been recorded 

 as British. 



1. V. microsticta Xyl. Mem. Soc. 

 Cherb. t. v. (1857) p. 117; Lich. 

 Scand. p. 183, t. i. f. 8. Thallus 

 effuse or subdeterminate, unequal, 

 rimose or granulato-pulverulent, sub- 

 leprose, whitish (K - , CaCl ). Apo- 

 thecia moderate,promiuent, rotundate, 

 above plane or unequal, often 2-3 

 confluent, white-suffused or denudate, 

 concolorous within ; spores ellipsoid 

 or ovoid, 0,225-0,350 mm. long, 

 0,095-0,115 mm. thick; hymenial gelatine and the thecae deep 

 blue (then often denigrate) with iodine. Cromb. Journ. Bot. 1882, 

 p. 274. According to Th. M. Fries (Lich. Scand. p. 322) it is 

 Pertusaria rlwdocarpa Koerb. Syst. Lich. Germ. p. 384, " sec. spec, 

 orig." ; but as Koerber's diagnosis by no means corresponds, the 

 specific name of Xylander must be adopted. 



When sterile and less developed the plant looks quite like a leprarioid 

 or variolarioid state of some Pertusaria. The apothecia are innate in the 

 thalline glomerules, subglobose or at length depressed ; in the two 

 British specimens they are only sparingly present in a rightly developed 

 condition. 



Hab. On the ground in an alpine situation. Distr. Extremely local 

 and scarce on one of the N. Grampians, Scotland ; though it probably 

 also occurs corricolous in the same district. B. M. : Ben Avon, 

 Braemar, Aberdeenshire. 



Subtribe IV. THELOTREMEI Xyl. Lich. Scand. (1861) p. 183, 



emend, apud Stiz. St. Gall. Xat. Ges. 1880, p. 394. 

 Thallus crustaceous, continuous, areolate or pulverulent, in- 

 ternally containing gonidia. Apothecia urceolato-impressed, often 

 with double margin : spores variable in number, plurilocular 



X -350 



Fig. 71. 



Varicellaria microsticta Nyl. 

 A spore, x350. 



